Electrodeposition of metal on hollow articles.



E. FRIEDHBIM.,

TOSTON 0F METAL ONHOLLOW ARTICLES.

APPLIGATIOR rILxn mn. 26, 1901.

ELECTROD Patented Mar. 23, 1909.`

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E. PREDHEIM.

ELEGTBOD-POSITION OP METAL (YN HOLLOW ARTICLES.

'I AYPLIOATIOH FILED MAR. Z8, 1907.

Patented Mar. 23, X909.

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WITNESSES;

ERNEST FFMEDHE; m,

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UNITED STATES PATENT OFFICE.

ERNEST FBIEDHEIM, F PARIS,IFRANCE.

Specification of Letters Patent.

ELCTROEPOSITION 0F METAL ON HOLLOW ARTICLES.

Patented March 23, 1909.

Application led March 26, 1907. Serial No. 364,69.-

lThis invention relates to the electro-deposition of metal on hollow articles.

It is well known that electrol 'tic' deposits cannot be obtained, or can -,o y be poorly' obtainedfpn hollow cat hodcs, and particug...jlarly on tubular catliodes of small section,

, owing to the fact that he electrolyte which -'l cannot be stirred or agitated inside the tubes', becomes weaker and weaker as the process continues, Hand, moreover, the de- .xcomposition does not occur in ethe same proportions as the body of the elcctrolvtic ath, whence it follows that the electrolyte ''ll'very soon ceases to be capable of effecting f a. satisfacto metallic deposit, the deposit becoming,r m' inside the tube and only being .produced at the extremities of the latter.

-lhis disadvantage has vbeen partly niet by .30 arranging arts corresponding to the tubular parts of t e articles to be manufactured, .vertically in theelectrolytic mth and inserting,` into said-bodic.s, anodcs i'n the form of rods, conforiiiing--as regards length and 'B this method an electrolytic deposit may c obtained throughout the whole length of the tube; but it is very often found that. owing,r to the anode .and cathode being very close 40 to each othen short circuits occur between them and obviously prevent metallic deposits, the dep'osit on the whole boing so irregular as to 4i'cnder this method unfitfor industrial purposes. v The object of'clic present invention is to avoid the reduction o these short circuits, and the esircd result is attained by surrounding the anode with aV perforated in sulating la yer which renders a direct contact between t e anode and cathode impossible, effective depolarization being maintained by the openings provided in the layer surround` in the anode. cferring to the accompanying drawings, 5b Figure 1 is a. view, showin the relai ive arrangement of the individua anodes with the main anode, the insulating materialtlieieon,

and (in section) the tubular bodies .to be plated; and Fig. 2 is a view, partly sectional, of the means for relatively securing the individual anodes to the main anode. I

In the arrangement illustrated, a represents a hot table, maintained at the desired temperature-whenrequired to be heated--` bv a gas burner, h, placed beneath it.

. u b is a frame for limiting the spa-ce in which the easily melted metal c is t'o be poured, d being the rods oranodes which arc supported and adjusted by means of perforated plates espacsd apart, at the desired distance, by means of nuts 'f on adjusting screws g. When the rods are thus supported in an exact vertical position, tbe metal c is poured onto the table a., and, after it hasbecoine sufficiently cool' to support the rods d, the adjusting screws g, together with the plates e, are withdrawn.

The process of this invention is for the,A purpose of produein a cal-:c having a great number of holes, o an average section of (say) ten millimeters and spacediby eleven millimetersfrom center to center, leaving between thcni a wall of a medium section of one millimeter. The layer of copper to be obtained will average not lcss than one-fifth of a millimeter. For this purpose, a desired number of :modes is vertically arranged ou a common conducting support and within a corresponding number of hollow cathodcs, also arranged vertically. The exterior surface ofeach anode is covered, in the usual manner, with au insulating layer intended to prevent short circuits und having suitable openings which permit the metal of the anode to he f rccly and evenly passed to the walls of the cathode;

In practice thc operation is as follows: ll'hen the parts upon which the clcctrolytic deposit is to be eflccted are placed vertically as shown at m. Fig. l, there are introduced thcrcinto the rod-shaped anodcs d which are made to bear on the principal anode c placed at the bottom of the vat, so that there will be a perfect clcctric contact between' this anode and the rod-shaped :modes d, which have'been enveloped b means of an insulated surface arranger, either in the form of a continuous surface in which suitable openings are formed, said asin surface n or quite large as in surface n,

- or the surface may: be in the form' (n) of a other metal easily fusibc und susceptible of being mtu-lied by the current. uf ecctr@ ysis md which preseals 'the idx-@Junges of fvi `4r sa, further commi tn zs armdas.

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